Lightweight structural panel



Sept. 12, 1967 J. F. WEBER LIGHTWEIGHT STRUCTURAL PANEL 2 Sheets-Sheet 1 Filed Dec. 3, 1962 FIG. 1

E 8 W F N M Sept. 12, 1967 WEBER 3,341,395

LIGHTWEIGHT STRUCTURAL PANEL Filed Dec. (5, 1962 2 Sheets-Sheet 2 v '1 000 c) Fla/0 44. INVENTOR John F Wkber Fla/f United States Patent 3,341,395 LIGHTWEIGHT STRUCTURAL PANEL John F. Weber, Aurora, 11]., assignor to Solar Reflection Room Corporation, Warrenville, 111., a corporation of Illinois Filed Dec. 3, 1962, Ser. No. 241,968 11 Claims. (Cl. 161-113) This invention relates to an improved structural panel that possesses high strength and is comparatively light in weight. The invention also contemplates a method for making the panel.

The panel of the invention is of laminated or sandwich construction, comprising a pair of spaced parallel skin members of sheet plastic material and a light weight core of sheet material between and secured to the skin members. The core has spaced parallel portions extending transversely of the panel, and these core portions are inclined to the planes of the skin members.

The structural panels of the invention may be made in various shapes and sizes, and by way of example a typical commercial panel may be rectangular in shape, 34 /2 inches in width and 13 feet in length. A panel of this shape and size is particularly suitable for roof and Wall applications.

The panel of the invention finds numerous uses, both on the inside and outside of buildings or other enclosures. For example, the present panels may be used in dwellings, patio enclosures, car ports, garages and garage doors, swimming pool enclosures, commercial buildings, schools and the like. Examples of interior uses are room dividers, doors, shower enclosures and the like.

The panels of the invention may be opaque, translucent, or transparent, and the plastic skin members may be given any desired coloration. When translucent, the panels have a light diffusing characteristic that softens the direct rays of the sun. In addition, the parallel portions of the core may be oriented in such manner that rays of the sun are rejected during the summer and admitted during the winter, thereby giving the panel a solar characteristic.

Laminated panels of the present type inherently are subject to a certain amount of internal condensation. The construction of the present panel is such that condensation effects are minimized, and the small amount of condensate that may develop readily is drained away or evaporated.

Several forms of cores are illustrated and described herein. Each has spaced parallel portions inclined to the planes of the skin members, and these portions have a mechanical as well as an adhesive bond with the skin members.

Other objects, advantages and features of the invention will be apparent as the description proceeds, reference being had to the accompanying drawings wherein various forms of the invention are shown. It is to be understood that the description and drawings are illustrative only, and that the scope of the invention is to be measured by the appended claims.

In the drawings:

FIG. 1 is a diagrammatic perspective view of a building panel embodying the invention and constructed in accordance with the method of the invention.

FIG. 2 is an enlarged fragmentary perspective view of the panel shown in FIG. 1.

FIG. 3 is an enlarged perspective view of one form of core used in the invention.

FIG. 4 is a fragmentary longitudinal sectional view showing one stage in the construction of subject panel.

FIG. 5 is an enlarged fragmentary sectional view showing another stage in the construction.

FIG. 6 is a fragmentary longitudinal sectional view through a completed panel.

FIG. 7 is a fragmentary of the core shown in FIG. 3.

elevational View of a portion FIG. 8 is a fragmentary plan view of a modified form core in an intermediate stage of construction.

FIG. 9 is a fragmentary longitudinal sectional view of a panel having still another modified form of core.

FIG. 10 is a fragmentary elevational. view of a portion of the FIG. 9 core in an intermediate stage of construction, and

FIG. 11 is a fragmentary perspective view of the core shown in FIG. 9.

Referring now to the drawings, FIG. 1 is a somewhat diagrammatic perspective View of a structural panel 15 embodying the invention. Panel 15 comprises an upper skin member 16, a spaced lower skin member 17 and a core 18 of sheet material extending between and secured to the skin members. As shown, panel 15 is rectangular, but it may have other desired shapes.

Skin members 16 and 17 are comparatively thin sheets of plastic material, for example a polyester resin. The plastic material preferably contains fibrous material such as glass fiber. Thus, the preferred material used in the skin members is of the type commonly called fiberglass.

The plastic material in skin members 16 and 17 may be opaque, translucent, or transparent, depending on the of translucent character.

Core 18 consists of sheet material, usually relatively thin sheet metal such as aluminum or the like. While various forms of core are shown, the core of the invention is characterized by spaced parallel portions extending transversely of the panel. The spaced parallel portions are secured top and bottom to skin members 16 and 17, and are inclined to the planes of the skin members.

The top and bottom margins of the spaced parallel core portions are embedded in the skin members, and have spaced apertures located at least in part within the bodies of the skin members. The plastic material of skin members 16 and 17, which is used in liquid form during construction of the panel, interlocks with the marginal apertures and establishes a mechanical as well as an adhesive bond with the core portions. The core portions thus are rigidly secured to the skin members.

Referring to FIGS. 17, core 18 is formed from a continuous piece of sheet material having transverse corto each other. The folds of the transverse corrugations illustrated in FIG. 4

and 35.

The apertures at the top and bottom margins of the spaced parallel core portions, located in thefolds of the corrugations, are designated 38 (large) and 39 (small) in FIGS. 3, 5 and 7.

A modified form of core 18a is shown in flat or precorrugated condition in FIG. 8. Core 181:: is adapted to be bent on fold lines 40 and 41, and spaced apertures 42 are provided on these lines to establish mechanical bond with the skin members.

Cores 18 and 18:: are corrugated as shown in FIGS. 4 and 6 so that adjacent core portions form substantially an equilateral triangle in cross section with the associated portion of the skin member. This arrangement imparts unusually high transverse strength to the panel.

Referring to FIGS. 9-l1, core 18b comprises spaced parallel. portions 44 that are embedded top and bottom in skin members 1611 and 171). As best shown in FIGS. 9

and 11, spaced parallel core portions 44 are inclined to the planes of the skin members.

The top and bottom margins of the spaced parallel portions 44 are bent along lines 46 and 47 (FIG. and spaced apertures 48 are provided along these lines. Apertures 48, of course, cooperate to establish good mechanical bond with skin members 16b and 171).

Core 18b shown in FIGS. 9l1 also includes transversely spaced longitudinal portions 50 that cooperate to tie together the inclined spaced parallel portions 44. Portions 50 preferably terminate at the top and bottom short of engagement with skin members 1612 and 17b, as shown in FIG. 9, thereby providing air circulation and condensate drainage transversely of the panel, as in the two cores previously described.

In panels having opaque skin members, it is immaterial from the light-transmitting standpoint whether or not the core portions are perforated, or whether the core portions are made of light-reflective material. However, even in the case of opaque panels, it often is desirable to perforate the bodies of the core portions in order to reduce weight. Thus, core portions 20, 21, 24, 25, etc., (FIG. 4) may he perforated as shown in FIGS. 2, 3 and 7. The perforations, of course, should be of such size, shape and distribution that the weight of the core is reduced substantially, but the structural strength is maintained.

The arrangement of perforations shown in FIGS. 3 and 7 has been found particularly satisfactory from both the weight and strength standpoints, as well as the standpoint, presently to be mentioned, of light transmission. Referring to FIG. 7, the body of the core portion there shown has spaced perforations 39a of small size arranged in a pattern of rectangles with a perforation 38a of larger size in the center of each rectangle.

In panels having translucent or transparent skin members, it is desirable for the core to have perforations, or the equivalent, permitting the passage of light. Also, it usually is desirable for the sheet material used in the core to have a light reflective characteristic.

The perforations shown in FIGS. 3 and 7 are particularly satisfactory from the standpoint of light transmission and pleasing geometrical appearance, to the extent visible through the skin members. These perforations provide about 44% open area. In addition, the surfaces of the core portions and the Walls of the perforations serve to reflect light within the panel, much of the light being diffused through the skin members.

Core 18a shown in FIG. 8 has a somewhat different pattern of perforations. There, each core portion 52, 53 and 54 has spaced parallel perforations 55 of elongated shape. The axes of perforations 55 in each core portion are inclined to the axis of the portion, and the inclinations in adjacent portions are opposite, thereby giving a herringbone effect.

Referring again to FIGS. 91l, inclined core portions 44 may or may not have perforations other than the perforations 48 provided for bonding purposes. Where perforations in the bodies of core portions 44 are not used, the panel with its inclined core portions may have a solar characteristic that rejects the direct rays of the sun during the summer and admits them during the winter. This result, of course, is achieved by proper orientation of the core portions with respect to the path of the sun, and proper inclination of the core portions.

The various panels previously illustrated and described, regardless of the particular form of core or whether the core portions are perforated, all are made by essentially the same method. This method now will be described.

The length and width of the desired panel first is established. Thereafter, a flat-bottomed receptacle (a portion of which is designated 60 in FIG. 5) having these internal dimensions is used, the receptacle being disposed horizontally.

The bottom of the receptacle is covered with a layer of suitable liquid plastic material '61, for example a polyester resin. The thickness of the layer of plastic material (exaggerated in FIG. 5) is of the order of inch minimum. As a practical example, about /2 pound of liquid plastic per square foot of area provides a skin member of satisfactory thickness.

Before or after the liquid plastic material 61 is placed in the receptacle 60, a mat or blanket 62 (FIGS. 4 and 5) of fibrous material, for example glass fibers, may be placed in the receptacle.

A core 18, 18a, or 18b, coextensive in area with the bottom of receptacle 60, is placed in the receptacle, the inclined core portions extending transversely of the receptacle. The margins of the core portions adjacent the receptacle bottom have apertures that are submerged at least in part below the surface of liquid plastic material 61, thereby insuring that the plastic material extends through the apertures to establish a mechanical bond.

The plastic material is allowed to harden, and thereafter the partially formed panel is removed from the receptacle. At this stage, the partially formed panel comprises the core and one skin member.

Next, the bottom of the receptacle again is covered with a layer of liquid plastic material 61, as previously, and

a mat or blanket 62 of fibrous material also may be,

placed in the receptacle. The partially formed panel is inverted and placed in the receptacle. The then lower margins of the core portions have spaced apertures that are submerged at least in part below the surface of the plastic material. After the plastic material is allowed to harden, the completed panel is removed from the receptacle.

From the above description it is thought that the construction and advantages of the improved panel and method of making same will be readily apparent to those skilled in the art. Various changes in detail may be made without departing from the spirit or losing the advantages of the invention.

Having thus described the invention, What is claimed as new and desired to secure by Letters Patent is:

1. A structural panel comprising:

a pair of parallel skin members in spaced, opposing relation, said skin members of sheet plastic material; and

a core of sheet material secured to and extending be tween said skin members and coextensive therewith, said core having spaced parallel portions extending transversely of the panel, said spaced parallel portions inclined to the planes of said skin members, the margins of said spaced parallel portions embedded in said skin members and having spaced apertures located at least in part within the bodies of said skin members.

2. The panel of claim 1 wherein said spaced parallel portions of said core have perforations of such size, shape and distribution that the weight of said core is reduced substantially and the structural strength of same is maintained.

3. The panel of claim 2 wherein said skin members are translucent.

4. The panel of claim 2 wherein said skin members are translucent and said core is of light-reflective material.

5. The panel of claim 4 wherein said spaced parallel portions of said core have spaced perforations of small size arranged in a pattern of rectangles and a perforation of larger size in the center of each rectangle.

6. The panel of claim 4 wherein said spaced parallel portions of said core have spaced parallel perforations of elongated shape, the axes of said perforations inclined to the axes of said portions.

7. The panel of claim 1 wherein said core is a continuous piece of sheet material having transverse corrugations, the folds of said corrugations embedded in said skin members and having said spaced apertures.

8. The panel of claim '7 wherein said skin members are translucent and said core is of light-reflective material.

9. The panel of claim 8 wherein said spaced parallel portions of said core have spaced perforations of small size arranged in a pattern of rectangles and a perforation of larger size in the center of each rectangle.

10. The panel of claim 8 wherein said spaced parallel portions of said core have spaced parallel perforations of elongated shape, the axes of said perforations inclined to the axes of said portions with the perforations in adjacent portions inclined oppositely to provide a herringbone appearance.

11. The panel of claim 1 wherein said skin members are translucent and wherein said core includes transversely spaced longitudinal portions connected to said inclined spaced parallel portions.

References Cited UNITED STATES PATENTS 880,363 2/1908 Costigan 161-113 X 1,568,266 1/1926 Carrillon 52-565 1,700,512 1/1929 Pedersen 25-154 2,077,989 4/ 1937 Daubenspeck 52-565 3/ 1943 Foreman 52-565 3/1953 Moore 52-383 X 9/1954 Carr 20-565 3/1958 Holland 52-266 10/1958 DeSWart 52-618 9/1960 Merriman' 161-113 12/1961 Osborne 20-5615 8/1964 Trenner 52-309 11/1964 Faccin et a1. 161-113 FOREIGN PATENTS 3/1954 Belgium.

5/1919 Great Britain.

6/ 1941 Great Britain.

2/ 1955 Great Britain.

2/1961 Sweden.

FRANK L. ABBOTT, Primary Examiner. HENRY C. SUTHERLAND, Examinen M. o. WARNECKE, Assistant Examiner. 

1. A STRUCTURAL PANEL COMPRISING: A PAIR OF PARALLEL SKIN MEMBERS IN SPACED, OPPOSING RELATION, SAID SKIN MEMBERS OF SHEET PLASTIC MATERIAL; AND A CORE OF SHEET MATERIAL SECURED TO AND EXTENDING BETWEEN SAID SKIN MEMBERS AND COEXTENSIVE THEREWITH, SAID CORE HAVING SPACED PARALLEL PORTIONS EXTENDING TRANSVERSELY OF THE PANEL, SAID SPACED PARALLEL PORTIONS INCLINED TO THE PLANES OF SAID SKIN MEMBERS, THE MARGINS OF SAID SPACED PARALLEL PORTIONS EMBEDDED IN SAID SKIN MEMBERS AND HAVING SPACED APERTURES LO- 